Method of impregnating stakes, posts, poles, and the like



Jan. 9, 1940. w, LUDWlG 2,186,648

METHOD OF IMPREGNATING STAKES, POSTS, POLES, AND THE LIKE Filed Feb. 16, 1957 2 Sheets-Sheet 1 IN V EN T07? Jan. 9, 1940. w, LUDWlG 2,185,648

METHOD OF IMPREGNATING STAKES, POSTS, POLES, AND THE LIKE Filed Feb. 16, 1 93? -2 Sheets-Sheet-Z Patented Jan. 9, 1940 UNITED: STATES.

2,186,648 METHOD OF. IMPREGNATING STAKES,

rosrs, POLES, AND THE Walter Ludwig, Konigsberg, Germany, assignor of one-half to the. firm of Ostpreu ssen-werk Aktiengesellschaft, Konigsberg, Germany U Application February 16, 1937, Serial No. 12 6,049

In Germany February17, 1936 I 4 Claims.

When impregnating wooden stakes, posts, poles and the like, the impregnating agent has hitherto been introduced from the peripheral surface to the core, or, if the member contained an 5 axial passage, it was introduced from the passage radially outwardly, or the impregnating agent was forced into thewood at one end until it appeared at the other end. e

In the first of the above mentioned procedures the impregnating agent ofttimes does not panetrate the sap woodsuificiently, that is, it may not go entirelyto the core. In that case the wood around the core which is partially impregnated, or not impregnated at all,'is subject to rot, which 1 of course" is extremely detrimental to the wood.

This is particularly dangerous because the condition of the wood cannot be, perceived irom'the outside.

If the posts; are hollow or otherwiseprovided with an axial passage, the impregnating agent passes radially outward from the passage, and in this case-it sometimes happens that the'outermost portions of the sap wood are not sufiiciently impregnated.- It appears from the above facts that impregnating methods in which the impregnating agent passes radially through'the wood are unsatisfactory in that the wood is insufliciently impregnated eitherat the outer portions of the sap wood or in the inner portions near thecore. This condition'canbe improved slightlyif the wood, prior to applyingthe impregnating agent, has had the air removed before incorporating the impregnating-liquid under high pressure. Axial impregnation can be carried out only with sapfresh wood, that is, wood having bark-and bast. The impregnating agent isintroduced through the end grain, generally from the top end of the trunk, and it is necessary to .displace the sap with impregnating liquid in order to place the wood in proper conditionto retain the impregnating liquid. I

In this method the impregnating liquid is distributed so that the greatest amount of it is found at that end of the wood at which it was introduced, and a smaller amount at the opposite end. This is the case, at least as long as it takes for the impregnating liquid to fully saturate the colloidal wood, at which time the distribution of the liquid becomes more equalized. This state is attainable, however, only after a longtime, within which a certain portion of the impregnating agent may be lost. Impregnation is generally discontinued when the ratio. between the two ends. of the wood has become about. 0.5 or 0.66:1. If the. impregnating-liquid contains substances. re-

. in consequence of which unequal (c1. ai -24) tained or absorbed in thewood, the state of unequal distribution is particularly perceptible.

Apart from the impregnation in an axial direction, the distribution of impregnating liquid is not uniform radially, or in a transverse sec- 5 tional area. When animpregnating liquid is ap. plied at the end of'a trunk, it distributes itself radially only little by'little, so that at first only the innermost portions of the wood are impregnated, and the outer portions near the peripheral 10 surface of the trunk are only impregnated after a long time. The outer strata of the wood which conveys the sap is capable of conveying the impregnating liquid far better than the innerstrata, distribution of the liquid is attained in an axial direction if the impregnating procedure is not carried on long enough-to equalize the distribution of the liquid. It will now be clear that the manner of displacing the sap by the impregnating liquid in an axial 20 direction results in an unequal distribution of the liquid axially as well as radially, in consequence of which the life of the wood is shortened. In order to do away with the condition mentioned it is necessary to convert the pole, post, 25 etc., into a body which is mushroom-proof throughout its entire mass. Poles, posts, andthe v like are subject to the detrimental action of mush 2 rooms when they have been placed in the ground, and the strength of this action depends upon the 30 sort of-ground in which they are placed. 9

In order to make the matter clear, I refer to theaccompanying drawings. Figures 1, 2 and 3 are diagrams. Figure 4 is an axial section through apiece of the trunk, and Figure 5 is a 35. transverse section through the same piece, all as hereinafter fully described.

Referring to Figure l, w denotes a curve disclosing the degree to which a poleplaced in the ground is endangered by mushrooms, and mde- 40 notes the pole, the lower end m of which is the portion placed in the ground. The-course of the curve a shows that it is not economical to render the pole mushroom-proof along its entire length. It would be more economical to operate 45 insuch a manner that the degree of immunity would correspond to the curve b, but. this result could not be obtained by any of the existing methods. It can be, andis, however, obtained by means of the present improved method in 50 which the impregnating liquid is incorporated into the wood simultaneously from both ends, that is, from the top endto the bottom end and reversely at the same time. If desired thereafter,

radial impregnationmay. alsobe employed, like- 55 wise iri two directions opposite to each other, that 'is, radially outwardly and from the periphery in but this procedure entails considerable disad vantages. A long time is required, and the impregnating liquid introduced during the second step or phase drives back the impregnating liquid introduced during the first step or phase until the second step liquid arrives at the point where the first step liquid has been driven into he wood. w I

When introducing impregnating liquid simultaneously from both ends of the trunk or pole, as is done in the present improved method, the two u nt of p natin l qu d 1 not counter eanother, so as to hinder each other. u pr ision is made that t ey lea e he run r. po about in the middle portion of the same by passn ad al y utwa dly, r wh c pu p se. a 1 .1 rality of axially extending slots is provided, as illustrated by way of example in Figures 4; and 5. More properly, these slots may be said to extend inthe direction of the fibers of the wood, as well as radially. In Figures 4 and 5, l denotes the trunk, and 3 denotes longitudinally or axially extending slots which are uniformly distributed about the circumference of the trunk. At the points where these slots are located, the bark and the bast are removed, and the slots extend radially from the core to theiree outer surface, as shown in Figure 4, which also shows that the slots maybe trapezoidal in shape, which means, that their sectional area is enlarged in an outward direction. But I wish it to be understood that an en a e n fthesee iena ea ma ake ac also in the circumferential direction of the trunk, as has b en i is ra ed i ur her may e e o e dev e o t e other, bo -to he fli numera Li Fi ur s ande deno es th seaweed. Whe e s umer 3 ,d n t etlie to e Wood; h i ner l gth .v oi t e. ra ezoidal lot ext nd alone the. eoreweqd an the O ter len h 6 en alon the s n, o a the u sur a thereof, Th best a d the bark a e no shown n i sur s i iidfi- O i o the pos ilt of a n h shape of e slo or wba ey o he a e th o n s ma e. n opportrinity fo ed t a ommod e he w r in n q e ur t he ind o we nd t0 he nn structu reo a e a o he e t of t e fall of the impregnating liquid from the recepael c nt n n t. i b in under tood that th receptaele is locatedat a certain height above the pole or trunk, which lies horizontalwhile being s b ect d o t e mpre p r t n- When the. impregnation is carried out with the pole or trunk l lyinghgrizontal, and a receptacle co ai i the presnetine qu d a ra d ufe n .h habe e it he, fall s t l ed n o halves of the trunk, in opposite directions, and the length of time necessary for complete impregnation is only about half the time necessary to cause the liquid to penetrate the wood from one end to the other, and reversely, in two stages. Also, the amount of impregnating liquid used is only half. as much, since the amount of this liquid used in the first stage of the reverse end process is a loss, because the liquid used in the second stage drives it out, as has already been described in a preceding part of the specification. The method of introducing or incorporating the impregnating liquid at the same time at both ends of the trunk or pole so as to produce two currents flowing toward each other presents the following advantages:

(a) The entire amount of the impregnating agent employed is distributed economically along the length of the pole in proportion to the danger from mushrooms in such a manner that at the ends of the poles which are most endangered the largest amount of the impregnating agent is present, and inthe middle portion, where there is the least danger, the smallest amount of the agent is present. The distribution is then such a one as indicated by the dotted line or ideal curve I in Figure 1 other words, the most perfect andmost ee gnomical' utilization of the impregnating agent is attained by employing my improved method.

thee eei pe emp y ier carr n hig olta e. Wires Q dinar l the current mus e turt e Qfi While tberqle seine impre na d eevered; Thi be ebvia esib ni ans oi e Pre ent ieventieeuwweh renders. it po sible eflexr teilierei e e the to .l9 ?9 9il ei a erme Pro e ti e so ut on. o to a comparati ely short action of a stronger solution, V V

T e imultaeee s.iirirresnat qnintwe Q recti ons counter to one another entails no dinic lty w at ere nl Qaeel i'ated recepta e or r a in l qu d need e d, a d n hing else isrequired butseparate pipes to conui' e i ii dte ear h. n 9? the ,7

Th m ho s ens e-able to. l 'eairiresli y s. of e w t ba i and arb r e rertie e. aw rd. .w iei eaten. the smallest amount of the protective substance w et or n a th pe ip era s rf e o th trunk, and this being so, those portions can be easily examined after the 'bas t and bark have e mo d o ,t possible. to ap ly any additional measure if suitable to the purpose.

Counter'to the effectoi theaxialintroduction or incorporation of the protective substance from both ends and at the same time, all other meth ods in which the protective substance is applied at the periphery of the trunk so as to introduce it inwardly fron the peripheral surface causes greater density of the substance at the periphery so that insufiiciently impregnated portions of the wood are invisible and inaccessible, But, if the wood is treated first axially in the manner described and then inwardly from the peripheral surface, then impregnation is not objectionable, in that no portions of the wood are insufiiciently impregnated. Normally the impregnation in this manner, that is, radially outwardly and inwardly from the peripheral surface, must be carried out in two work phases.

The impregnation radially outwardly is due to the axial impregnation which takes place not only axially but also laterally, or radially outwardly, there being attained in the wood a fall of impregnating liquid in two directions at right angles to each other. As the impregnation. is efifected axially as well as radially and in two directions, always counter to oneanother, there are consequently four ways in which the impregnating fluid exerts its effect. However, four working phases are not necessitated, but rather only two, of which the first effects the. impregnation in the two axial directions and in the direction radially outwardly, whereas thesecondphase is that in which the impregnation takes place from the peripheral surface inwardly.

I think myself to be the first who has. discovered and ascertained the. unequal'density of the impregnating substances in the wood and in lowest at the opposite end, where it may evengo down to zero. The greater the fall of pressure in the wood in a radial direction of the sectional.

area, the more uniform is the distribution of the impregnating substances over the sectional area of the wood, but it is better at the end of the pole to which the liquid was applied than it is at the opposite end. I u

i In the practical application of the present improved method, packingor tightening rings are applied to the ends of the trunk or pole, etc. The breadth of these rings can be varied according to the requirements,and also the sectional area of the openings or passages in the middle portion of the trunk can be varied and adjusted to the height of the fall of the liquid from the receptacle to the ends of the trunk. It is thus rendered possible to provide for a uniform distribution of the impregnating agent along the entire length of the trunk, as well as in the sectional areas of the same.

The fall in the longitudinal direction of the trunk will appear from Figures 2 and 3, in which, in the one case large lateral or radial passages, and in the other case small openings or passages, are assumed to exist. Referring to these figures: L denotes the length of the trunk; H denotes the pressure of the liquid at the exit end, that is, at the orifice of the radial passages; S denotes the height of the level of the impregnating liquid in the elevated receptacle; 0 denotes one of the exit openings, which is assumed to be large in Figure 2 and small in Figure 3. In both cases this opening lies about in the middle of the trunk. The line gz' indicates the course of the fall in the innermost portion of thesap wood, and a line ya indicates the course of the fall in the outermost portion of saidwood. The letter T indicates the radial fall. 1 y

The axial supply of the impregnating liquid in two directions counter to one another in connection with the provision of the tightening rings at the two ends of the trunk or pole constitutes not only a longitudinal incorporation of impregnating agent into the wood, but also a radial incorporation in the outward direction, whereby the impregnation is rendered excellently uniform over the entire sectional area of the trunk, this being especially true of the sap wood along the entire length of the trunk, and being further true if the duration of the impregnation procedure is restricted to a certain moderate period.

When a sap-fresh wood trunk is treated first in an axial direction, that is to say, in both axial directions counterto one another, and if that trunk-is then treated in the direction from the outer surface of the trunk to the core thereof, faults which might possibly occur in the older methods are completely obviated, which is another important advantage of fmy improved method. I

The radial incorporation of an impregnating or protecting substance may alsobe effected, in the case of a sap-fresh trunk, by'applying to the outer surface of the trunk; after the bast and bark have been removed therefrom, a salt solution which then penetrates into the wood by diffusion. It is then advisable to protect the thus treated surface from rain during the time in which thesalt solution is to act, possibly by a sort of roof over the trunk. The length of time necessary to carry out'this operation is considerably shorter than if an osmotic procedure is used.

It is likewise possible to let the axially impregnated trunk dry and impregnate it thereafter in a boiler under pressure with a salt solution or with tar-oil, provided that the sort of wood under treatment permits of such a procedure. If the protection procedure is carried out in this manner, that is, by the employment of a boiler and of pressure, after first being subjected to the axial impregnation procedure, the

two proceduressupplement each other, in that the salt solution or the tar-oil enters into the When the wood is exposed to wetness, for a long time, the

tar-oil passes from the cell walls into the cell cavities and exerts therein, in combination with the salt, a chemical-biological action, as Well-as a physical one, this latter effect being due to the water repelling action. of said oil.

I claim:

1. A process for the impregnation of fresh, sappy, Wood poles, masts or timbers comprising providing air openings near the center of the length thereof and extending substantially completely through the sap wood, then simultaneous- 1y, forcing impregnating fluid into each end of the pole, driving the sap of the pole out of said openings ahead of said fluid and continuing the introduction of said fluid until it passes out of said openings.

2. The process as specified in claim 1, particularly as applied to electric poles and the like, further comprising the provision in the member to be treated about equally remote from the ends thereof a plurality of radial. slot-like passages extending in the direction of the fibers and from the outer surface into the interior of said member.

3. The process as set forth in claim 1 further comprising the provision in the member to be tar-oil, this substance repels the water-and exerts a particularly useful effect in that it prevents the formation of mushrooms.

direction of the fibers and from the surface of the member radially into the interior thereof as far as the core wood, and substantially equally distributed about the circumference of the same, in such a manner that each of said passages has substantially the shape of a trapezoid, the short base of which is parallel to the axis of the membar and lies in the heart wood while the long stantially radially and completely through the fluid until it passes out of said openings and sap wood, then simultaneously forcing impregcontrolling the pressure serving to distribute the nating fluid into substantially the whole sap fluid radially in the pole by regulating the numwood area of each end of the pole, driving the her and size of said openings.

sap of the pole out of said openings ahead of said fluid, continuing the introduction of said WALTER LUDWIG. 

